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• Error while displaying RTP stream packets from udp port on Gstreamer

  20 octobre 2015, par Gaurav Singla

  I am streaming a live webcam using VLC to darwin streaming server.

  Then tried to play this live web cam feed on RTSP client using following

  GST_DEBUG=2 gst-launch -vvv playbin uri=rtsp ://172.19.91.21/channel.sdp

  Everthing works fine. output is coming on gstreamer window.

  I have reflect all the packest from DSS to RTSP client as well as on a udp_port. But when i tried to play RTP stream using following command

  GST_DEBUG=2 gst-launch-0.10 -vvv udpsrc port=5000 multicast-iface="lo" multicast-group="172.19.91.20" buffer-size=1000000 caps="application/x-rtp, media=video, clock-rate=90000, encoding-name=H264" do-timestamp=false ! rtph264depay ! decodebin ! autovideosink

  I am getting following errors

  0:00:07.108734201 7874 0x89d2a90 ERROR ffmpeg :0: : non-existing PPS referenced
  0:00:07.108803500 7874 0x89d2a90 ERROR ffmpeg :0: : non-existing PPS 0 referenced
  0:00:07.108824183 7874 0x89d2a90 ERROR ffmpeg :0: : decode_slice_header error
  0:00:07.108840903 7874 0x89d2a90 ERROR ffmpeg :0: : no frame !
  0:00:07.108859244 7874 0x89d2a90 WARN ffmpeg gstffmpegdec.c:2299:gst_ffmpegdec_frame : ffdec_h264 : decoding error (len : -1, have_data : 0)

  Please guide me how to solve this problem.

• phantomjs screenshots and ffmpeg frame missing

  20 octobre 2015, par Bussiness Way

  I have problem making video from website screenshots taken from phantomjs.

  the phantomjs did not make screenshots for all frames within the same second and even not all seconds there , there is huge missing frames .

  the result is high speed video playing with many jumps in video effects .

  test.js :

  var page = require('webpage').create(),
  
      address = 'http://raphaeljs.com/polar-clock.html',
  
      duration = 5, // duration of the video, in seconds
  
      framerate = 24, // number of frames per second. 24 is a good value.
  
      counter = 0,
  
      width = 1024,
  
      height = 786;
  
          frame = 10001;
  
  
  
  page.viewportSize = { width: width, height: height };
  
  
  
  page.open(address, function(status) {
  
      if (status !== 'success') {
  
          console.log('Unable to load the address!');
  
          phantom.exit(1);
  
      } else {
  
          window.setTimeout(function () {
  
              page.clipRect = { top: 0, left: 0, width: width, height: height };
  
  
  
              window.setInterval(function () {
  
                  counter++;
  
                  page.render('newtest/image'+(frame++)+'.png', { format: 'png' });
  
                  if (counter > duration * framerate) {
  
                      phantom.exit();
  
                  }
  
              }, 1/framerate);
  
          }, 200);
  
      }
  
  });

  this will create 120 image , this is correct count , but when you see the images one by one you will see many duplicate the same contents and many missing frames

  ffmpeg :

  fmpeg -start_number 10001 -i newtest/image%05d.png -c:v libx264 -r 24 -pix_fmt yuv420p out.mp4

  I know this script and ffmpeg command not perfect , because I did hundred of changes without lucky, and I lost the correct setting understanding .

  an anyone guide me to fix this ?.

  thank you all

• ffmpeg failed to open h264 codec

  29 novembre 2015, par Joseph

  I’m trying to extract frames from an existed video (h264), using the ffmpeg library.
  When use an avi video file (with mjpeg - motion jpeg codec), all works fine.
  (m_formatCtx->iformat = av_find_input_format("mjpeg") ;)

  When run on the mp4 with h264 codec, we get the following errors, and no luck !!
  We fail when try to retrieve stream information by calling :
  avformat_find_stream_info(m_formatCtx, NULL) ;

  The log :

  [h264 @ 02023460] non-existing PPS 1 referenced
  
  [h264 @ 02023460] non-existing PPS 1 referenced
  
  [h264 @ 02023460] decode_slice_header error
  
  [h264 @ 02023460] non-existing PPS 6 referenced
  
  [h264 @ 02023460] decode_slice_header error
  
  [h264 @ 02023460] no frame!
  
  [h264 @ 0201a880] decoding for stream 0 failed
  
  [h264 @ 0201a880] Could not find codec parameters for stream 0 (Video: h264): unspecified size Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  Could not find stream information

  Any idea ?

  the Code :

  We call

  CVideoReader::Open (file name , PRESET_MJPEG_CLOCKLESS_STREAM,
  IMAGE_FORMAT_RGB1)

  see below :

  bool CVideoReader::InitFormat(std::string _filepath)
  
  {
  
      m_formatCtx = avformat_alloc_context(); 
  
      m_formatCtx->iformat = NULL;
  
  
  
      if(m_videoPreset == PRESET_MJPEG_CLOCKLESS_STREAM)
  
      {
  
          m_formatCtx->iformat = av_find_input_format("h264");
  
         // Get timestamp from clock on arrival
  
          m_formatCtx->use_wallclock_as_timestamps = true;
  
      }
  
  
  
      int ret;
  
      // open input file, and allocate format context
  
      if ((ret = avformat_open_input(&m_formatCtx, _filepath.c_str(), m_formatCtx->iformat, NULL)) < 0) 
  
      {
  
          std::cerr << "Could not open source file" << std::endl;
  
          return false;
  
      }
  
  
  
      // retrieve stream information
  
      ret = avformat_find_stream_info(m_formatCtx, NULL);
  
      if (ret < 0) 
  
      {
  
          std::cerr << "Could not find stream information" << std::endl;
  
          return false;
  
      }
  
  
  
      m_videoStream = m_formatCtx->streams[0];
  
  
  
      av_dump_format(m_formatCtx, 0, _filepath.c_str(), 0);
  
      return true;
  
  }
  
  void CVideoReader::Open( char * _filepath, EVideoPreset _videoFormat, EImageFormat _imageDecodingFormat)
  
  {
  
      m_videoPreset = _videoFormat;
  
      if(!InitFormat(_filepath))
  
          return; 
  
  }
  
  
  
  
  
  CVideoReader m_vr = new CVideoReader ();
  
  m_vr->Open( (char *)inFile, CVideoReader::PRESET_MJPEG_CLOCKLESS_STREAM, CVideoReader::IMAGE_FORMAT_RGB1 );